The present invention relates to tobacco leaf processing and more particularly to the cutting of the tie-leaf on bundled leaf tobacco.
In certain tobacco-producing regions, farmers grade tobacco leaves and tie them in bundles, varying from 10 to 30 leaves each. A single leaf is wrapped around the butt end of the bundle and tucked in between the stems to secure the bundle. When these bundles are processed, they are laid across a conveying structure such that the bundles are 90xc2x0 to the direction of travel of the conveying structure with the butt ends closest to the person placing them. Typically, the first operation is the cutting of the tips of the bundles to segregate them for a different process. A tipping board is used to line up the tips of the leaves as they are placed on the conveying structure and then they pass by a tip cutting mechanism, such as large intermeshing circular blades. Once this has happened, the remaining part of the bundle is passed by a mechanism for cutting the tie-leaf so the bundles can fall apart and the individual leaves can be further processed. If the bundles are not tipped, the butt ends are just lined up manually and then passed by the tie-leaf cutting mechanism. The tie-leaf must be cut or else the bundle remains intact and cannot be conditioned or threshed efficiently.
There are several known mechanisms for cutting the tie-leaf on bundled leaf tobacco. One known mechanism includes two counter-rotating rollers, one above the other. The top one is cantilevered and pre-loaded to supply a downward force, and is equipped with planar blades spaced apart and parallel to the axis of rotation. This creates a mangle effect, and the planar blades cut through the tie-leaf, allowing the bundle to fall apart. Another mechanism is disclosed in U.S. Pat. No. 5,664,585. The ""585 patent discloses a rotating cylindrical cutting drum including arcuate cutting blades thereon to cut the tie-leaves.
These types of mechanisms have several deficiencies. Because of differing sizes of bundles, if the bundles are lined up for tipping, the butt ends may not be on line for the cutting mechanism. When a large bundle enters the cutting mechanism next to a small bundle, the blades may not act upon the small bundle. The action of the rollers/drum and blades under pressure damages the leaves in the bundle, causing the generation of dust and undesirable small particles. This is particularly bad where the tobacco is low in moisture. Bundles also cause the equipment to choke-up and frequent stoppages occur, costing expensive downtime. Because of the sharp blades, operators must take great care when unstopping them.
There is a need for a method and apparatus for cutting tie-leaves that has a cutting efficiency close to 100% and causes no trauma to the tobacco. There is also a need for a method and apparatus that does not obstruct the flow of tobacco, thus causing no stoppages.
It is known that a high-pressure liquid jet can cut a single tobacco leaf passed therethrough. However, this knowledge exists in areas quite unrelated to the present subject matter.
For example, U.S. Pat. No. 4,640,300 to Coleman discloses a tobacco stripping system for cutting successive individual tobacco leaves into strips by employing a set of three stationary liquid jet nozzles spaced apart by a predetermined distance related to the desired strip width. A conveying structure transports the leaves longitudinally through the streams of high-pressure liquid generated by the nozzles to provide three longitudinal cuts to strip the tobacco.
Applicant has found that it would be desirable to use high-pressure liquid jets to cut the tie-leaf on bundled leaf tobacco. However, a stationary jet arrangement of the ""300 patent would not be suitable for purposes of the present subject matter. A transverse cut within the butt end area is needed to cut the tie-leaf, which cannot be done effectively by the conveyor and a stationary jet arrangement of the ""300 patent.
The present invention is based upon the underlying concept that the disadvantages of the presently practiced procedures for cutting tie-leaves can be obviated by the use of a liquid jet to cut the tie leaves and more specifically to the creation of a workable method and apparatus combination for implementing the underlying concept.
It is an object of the present invention to provide the concept implementation described above. In accordance with the principles of the present invention, this objective is achieved by providing a method for cutting tying elements of successive tobacco leaf bundles, wherein the butt ends of the leaves of each bundle are grouped and secured together by a transversely extending tying element disposed in surrounding relation to the grouped together butt ends. The method comprises moving successive bundles along a predetermined path past a cutting station with the grouped butt ends of successive bundles disposed transverse to the path within a predetermined transverse position within the path. A liquid jet configuration is established at the cutting station and moved through a repetitious path having a transverse extent greater than the transverse extent of the tying elements within the transverse position of the butt ends of the bundles. The moving jet configuration is directed onto the butt ends of successive bundles during the movement thereof along the predetermined path through the cutting station to transversely cut the tying elements thereof.
In accordance with another aspect of the invention, there is provided an apparatus for cutting tying elements of successive tobacco leaf bundles, wherein the butt ends of the leaves of each bundle are grouped and secured together by a transversely extending tying element disposed in surrounding relation to the grouped together butt ends. The apparatus comprises a bundle moving structure constructed and arranged to move successive bundles along a predetermined path past a cutting station with the grouped butt ends of successive bundles disposed transverse to the path within a predetermined transverse position within the path. A jet providing structure directs a source of liquid under pressure into a liquid jet configuration. A mounting structure is constructed and arranged to mount the jet providing structure on a frame for movement through a repetitious path having a transverse extent greater than the transverse extent of the tying elements within the transverse position of the butt ends of the bundles. A power operated moving mechanism has structure constructed and arranged to move the jet providing structure through the repetitious path so that the liquid jet configuration is directed onto the butt ends of successive bundles during the movement thereof along the predetermined path through the cutting station to transversely cut the tying elements thereof.
These and other objects, features, and advantages of this invention will become apparent from the following detailed description when taken into conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, the principles of this invention.